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Discuss anything and everything else here, including mobile devices.enTue, 31 Mar 2015 19:02:23 GMTvBulletin60http://www.phoronix.com/forums/images/misc/rss.pngPhoronix Forums - General Hardwarehttp://www.phoronix.com/forums/
Security warning: uncommon DRAM bug allows privilege elevation!http://www.phoronix.com/forums/showthread.php?116116-Security-warning-uncommon-DRAM-bug-allows-privilege-elevation!&goto=newpost
Sat, 21 Mar 2015 17:39:03 GMTSecurity researchers from Google's Project Zero have found rather uncommon way to escalate privileges in virtually any OS. Few months earlier there was rather uncommon security issue report in LKML. This attack has been named rowhammer, thanks to access pattern which implies excessive use of single row line of DRAM.

What is the problem? DRAM stores bits as charge in capacitor in array of rows and columns. This is generally compact, only requires 1 transistor to work, but charge could dissipate over time so regeneration cycle needed. Some researchers figured out that specially crafted DRAM access pattern could cause excessive leakage on "abused" DRAM row. This in turn can cause bit flip in some cells of row line before refresh cycle occurs, causing DRAM content corruption. This issue has been recognized in DDR4 and DDR4 controllers are required to address this issue. However, it does not tells anything about earlier DDR memories which are widely used to the date.

Some experiments revealed that it is possible to create problematic access pattern under software control. It may or may not cause DRAM data corruption, depending on DRAM manufacturer and IC. Yet, unexpectedly large number of systems proven to be affected. This is hardware-level trouble and OS can't address it directly. In some cases OS can work it around, but it really depends. Catch here is that very specific DRAM access pattern required. This could only be achieved if attacker can flush CPU cache. Else repeated requests will hit CPU cache, failing to abuse DRAM row. On some systems like ARM, cache flushing requires privileged code and it can get on the way, thwarting application level attacks. But on x86 any user mode program can flush cache. This is unprivileged instruction. It can't be intercepted by OS. So x86 systems lack obvious fix for this problem.

Initially it has been thought it only usable for relatively useless memory corruption, causing DoS. Yet, Google's researchers found ways to use this problem to escalate privileges from usermode to kernel, without need of root, or anything, by just corrupting proper memory region. So it could be far more harmful than expected. Actually, there are many ways to trigger this nasty DRAM bug. It is speculated things can go as bad as some malicious java script on some web page can find way to provoke problematic memory access, gaining kernel mode rights if attack has been successful, being able to completely overtake control over system as the result.

Of course Google devs coded tool and put it on github, which allows to check if your system haves problematic DRAM and affected. I think it could be worth of news article on Phoronix, since it also affects *nix like systems and PoC from Google actually deals with these. Yet I can't remember this in Phoronix news. So here it goes.
]]>General HardwareSystemCrasherhttp://www.phoronix.com/forums/showthread.php?116116-Security-warning-uncommon-DRAM-bug-allows-privilege-elevation!SecureBoot on Windows 10 computers may not be disable-ablehttp://www.phoronix.com/forums/showthread.php?116088-SecureBoot-on-Windows-10-computers-may-not-be-disable-able&goto=newpost
Sat, 21 Mar 2015 08:45:43 GMTWhile previously MS required x86 computers to be able to disable SecureBoot, with Windows 10 it is no longer a requirement.
...While previously MS required x86 computers to be able to disable SecureBoot, with Windows 10 it is no longer a requirement.

The ColorHug ALS is an ambient light sensor developed by Richard Hughes to dynamically control the brightness of laptop panels -- for laptops that don't have a built-in light sensor for said purpose...

Yesterday I wrote a bit about the 2U server chassis I've been using that cost just $69 USD a piece. Meanwhile for fitting standard ATX motherboards and larger full-size graphics cards, there's a 4U chassis I've bought several of thus far that retails for just over $50.

So far, my modest research has turned up the Asus N751JK. I was wondering if anyone has experience with Asus laptops and Linux, do they work well together?
]]>General HardwarePacofhttp://www.phoronix.com/forums/showthread.php?115849-New-Linux-LaptopStarTech 42U Rack Cabinet Make For Nice Low-Cost, Rackmount Setupshttp://www.phoronix.com/forums/showthread.php?115839-StarTech-42U-Rack-Cabinet-Make-For-Nice-Low-Cost-Rackmount-Setups&goto=newpost
Sat, 14 Mar 2015 15:20:18 GMT*Phoronix: StarTech 42U Rack Cabinet Make For Nice Low-Cost, Rackmount Setups*
In the process of building our new open-source, Linux benchmarking...Phoronix: StarTech 42U Rack Cabinet Make For Nice Low-Cost, Rackmount Setups

In the process of building our new open-source, Linux benchmarking test farm the server racks I settled for are the StarTech.com 42U rack cabinets. I've bought three of these StarTech.com 42U (4POSTRACK42) racks in the past few weeks and have been happy with their quality for low-price and it includes casters, levelers, and cable management hooks.

With the recent launch of the Raspberry Pi 2, I had immediately ordered one for some ARM hacking, as the price-performance angle was finally acceptable. Then it hit me, I had no idle screens with HDMI/DVI input.